I love the brief! It's larger in outline than the city, yes, but it's actually not that big because it's flatter (has less depth to it). That means it sits more nicely against the body when carried. First and foremost you need to decide whether you need a shoulder strap. Then it's the city for you. But keep in mind that the brief's handles are longer so it's easier to carry it over the shoulder.
I prefer the brief to the city but I know I'm in the minority here. And I'm also quite a lot taller than you so that's something else to consider. Have a look at the modeling thread -- there's loads of pics there of the city and the brief being carried.
GL, let us know what you decide.